Testing Methodology: Measured using Arta via IEC 711 coupler to Startech external sound card. 7-9KHz peaks may be artefacts/emphasised due to my measurement setup, less so with deep fit. Measurements besides channel balance are volume matched at 1KHz. Fit depth normalised to my best abilities to reduce coupler resonance. Still, due to these factors, my measurements may not accurately reflect the earphone or measurements taken by others. I gave the Benbulbin 100hrs of burn-in to ensure maximum performance prior to subjective breakdown.
Nostalgia Audio’s marketing is scarce and brief, but in conversation with Adrian, he did mention that the Benbulbin targets a reference sound. It appears in measurement to be a bass-boosted DF neutral curve with a few key changes in the midrange itself. Sub-bass has obviously been brought forward with a wideband cut applied through the upper-bass/lower midrange retaining a clean tone. In addition, pinna gain has been cut by a few dB and the 4kHz region has been brought forward. The lower-treble is then tapered off more aggressively, imbuing a smoother articulation while leaving a small 6kHz bump to retain detail presence.
In turn, it doesn’t come across quite as linear as earphones following the DF neutral and Harman curves more closely, but has a very similar overall balance and character. Technically, the Benbulbin glimpses true stars in the high-end domain such as the Campfire Audio Andromeda or Fir Audio VxV, but falls just short of them in return for a more balanced and linear tonality. Few would doubt this is a high-end design in either regard. On a side note, for my personal preferences, the Final E-tips offered the best synergy, slightly improving midrange coherence and providing a more defined bass response. These were used for the sound analysis below.
The Benbulbin offers a sub-bass focused low-end with a progressive cut through the mid-bass into a slightly recessed upper-bass/lower-midrange. It’s a moderate boost over your usual reference earphone but nothing that overly upsets the tone or timbre. Extension is what you would expect from a good DD implementation, providing clearly more slam and a more defined rumble than any BA monitor. While there are more aggressive, harder-hitting DD implementations out there, what this earphone excels more at is providing good depth and dynamics paired with excellent tightness and detail retrieval. The tuning showcases superb cleanliness too, mitigating boom and muddiness without missing body. Warmth is a touch diminished, however, as the sub-bass increases note body, the net result is a tonally transparent, faithful voicing that I can see few having complaints with unless you want more overt emphasis.
Getting more granular, the note presentation is agile and controlled with a slightly smooth over aggressive texture. This is because attack isn’t too aggressive, there isn’t a heap of pressure nor long lingering texture here, but rather a quick, tight impact at the very bottom prioritising snappy timing. Notes decay a touch faster than your average DD thereafter, contributing to excellent mid-bass definition and separation. Dynamics remain strong as well if not being outstanding, and this earphone likely won’t appeal to those wanting huge bass energy as a result. However, this isn’t a light footed sound either, as the sub-bass boost reinforces lows with a hearty yet very well-controlled rumble and slam. While I have found many sub-bass emphasized earphones to have diminished separation, due to the tightness and clean upper-bass tuning, this is actually a strong point here; the mid-bass showcases excellent definition and detail retrieval. The Benbulbin has a tight, snappy note presentation and a clean, satisfying tuning that is a pleasure to listen to.
I will preface this analysis by stating that the following comments will be relative to Harman-target IEMs from which the Benbulbin manages to sound reminiscent at a basic level while introducing its own distinct character. The midrange is immediately highly defined, resolving fine textures in instruments and vocals immensely well, whilst retaining a natural voicing and timbre. The tone is dead neutral and note body is somewhat thin. Despite this, the earphone avoids intensity due to its reduced pinna gain and minimal sharpness with its smooth articulation, managing to be more forgiving than most as a result. Separation, definition and clarity have all been enhanced via a wide-band upper-bass/lower-midrange cut paired with a small 4kHz bump. Secondly, the 3kHz region responsible for pinna gain has been toned down as has the lower-treble, redeeming smoothness and avoiding over-forwardness. What remains is excellent tri-frequency balance and vocals in almost perfect harmony with instruments. As the sound has become slightly more upper-midrange biased, female vocals do tend to steal some spotlight and can sound a little bright and breathy on some tracks, if never becoming excessively intimate or peaky. Furthermore, a small centre-midrange hump ensures that male vocals never become overshadowed.
With my preferred Final E-tips, this imbalance is less apparent and they address the thinness to some extent as well by enhancing upper-midrange density – albeit, coherence remains reduced due to the lower-mid cut. While I would have preferred a more body, the Benbulbin is not a harsh, sibilant or hollow sound whilst epitomising tonal cleanliness and clarity. It also isn’t an earphone I consider overtly smooth or warm, but does come across as a little smoother and more refined than the average Harman earphone due to its toned down top-end. The smoother articulation especially takes intensity out of the sound, meaning that though female vocals are a little forward, they are never sharp, sibilant or metallic. That said, due to the uptick of upper-midrange quantity don’t expect huge coherence or a richly bodied presentation here; zero extension and openness have been sacrificed in the pursuit of a more forgiving sound. I do also acknowledge that many listeners enjoy having a more prominent female vocal but even if you don’t, I think most would be impressed by the Benbulbin’s midrange timbre and resolving power, especially with the right ear tips. It is a good solution for those that find Harman earphones a bit vocal-forward and shouty albeit some brightness in the upper-midrange has been introduced in return. This means you must pay particular attention to fit depth and tip selection. Once dialled in, the Benbulbin delivers a strong performance in essentially every regard.
The top-end is slightly smooth but in good coordination with the bass and midrange in terms of quantity, upholding its trend of excellent balance. It is defined by an impressively linear foreground with only a very small 6k bump, a dark background and subsequent rise in the upper-treble. Unfortunately, with E-tips, the 6k region becomes a bit more pronounced which can make treble sound just a little brittle. However, it isn’t a treble-forward earphone by any stretch, remaining smooth and clean relative to most competitors. This tuning has allowed Nostalgia Audio to achieve a revealing sound in the midrange whilst avoiding intensity and fatigue over longer listening. Treble itself is well-detailed and extended too. I’m not hearing the space and sparkle one would on a TOTL monitor, but definitely a stong performance suitable for the price. While treble is a touch laid-back, it is well-voiced with a keen note attack and a clean transient response that permits strong fine detail retrieval.
The foreground is flattered, with minimal peaking and resonance permitting a well-bodied and textured response. The middle-treble trough does mean decay, cymbals especially, can sound a bit dampened with a slightly muted shimmer. This contributes to a more grounded and foreground focussed presentation. Despite this, air and openness aren’t lacking with the lift in the upper-treble working to good effect alongside strong if not outlandish extension. The Benbulbin has good, not great background detail retrieval and ample extension to realise such a tuning. However, still don’t expect huge amounts of top-octave sparkle or energy here, it is working more to the benefit its spatial characteristics rather than creating huge audible micro-detail. While the Benbulbin isn’t a technical wonder, it is a clearly good performer in a strong price-class and is tonally refined to boot.
I really enjoy the soundstage performance of the Benbulbin too, and the performance here secures its spot as a competitive option in the high-end market. While not as spacious as Campfire Audio’s high-end monitors, it has a good balance between depth and width and expands beyond the head in both axis. I would put it about on par with something like the Soft Ears RSV, itself a strong performer. As vocals aren’t too forward, however, its sense of space is often exacerbated, maximising the use of its space. Imaging is very sharp, however, one thing to note is that I’ve found the performance here to be very fit dependent. Sizing down tips from medium to small allowed a deeper fit and noticeably sharper, more accurate imaging.
Due to the more conservative treble tuning, it isn’t especially holographic nor diffuse, but of respectable dimension and impressive organisation. Treble has quick transients and sharp if not highlighted directional cues. Localisation is pinpoint accurate, and the earphone has a good ability to position front to back in addition to left and right, besting most competitors. Layering also impresses, it does have higher contrast between foreground and background but individual layers also appear well-delineated and defined, especially in the midrange. Separation is a highlight too, especially with regards to its low-end. Small details shine through and are easily perceived by the listener.
The Benbulbin has a very low 11 ohm impedance and un-specified sensitivity though from testing I would gather that it is into the 110dB range making this an efficient and sensitive earphone.
Output Impedance Sensitivity
Switching between the Shanling M2X (1-ohm) and Hiby R6 (10-ohms) revealed that the Benbulbin is affected by output impedance similar to most hybrid/multi-driver earphones, albeit, the difference wasn’t as large as on some competitors. I noted a diminished top-end on the Hiby, forming a more L-shaped signature. While bass was similarly voiced on both, the midrange was smoother and more laid-back on the Hiby. Similarly, treble was notably blunted. It remained listenable, and a source with a single-digit output impedance like my Xperia 5 II rewarded with a perfectly enjoyable experience. Still, a low output impedance source is ideal to extract the best balance from this earphone. Users sensitive to highs may consider impedance adaptors to smooth off the top end to some degree.
The Benbulbin achieves a fine balance, being efficient but not overly sensitive. Switching between Shanling M2X and my desktop Topping 30 Pro stack revealed a more robust, dynamic bass, sub-bass especially and notably improved soundstage depth. While it remained a quick, tighter performer on the Shanling, the desktop source was more textured and defined in the bass with a noticably more authoritative slam at the very bottom. In addition, treble had a bit more body, being wispier on the Shanling. That said, a powerful source is definitely not required given that bass is already tight and well separated. In addition, on volume setting 0, zero hiss was audible on the Shanling M2X, where some more sensitive IEMs can reveal noise when the amp circuit is active.
Suggested Pair Ups
The Benbulbin is not source agnostic like some competitors but is relatively easy to drive given that most modern sources would satisfy its criteria. This earphone doesn’t require much driving power, nor a perfectly dark noise floor. Its tuning means it tolerates lower driving power well as definition remains strong even when driver control is not ideal. The main concern would be a lower output impedance, even a few ohms is fine and may even be preferred by some as it reduces brightness and increases smoothness. With regards to source tonality, this obviously most applies if it has a low output impedance or else other colouration will be introduced. The Benbulbin benefits from a slightly warmer source as it gives the midrange a bit more body.